A semiconductor device including compounds such as GaN and AlGaN has many merits such as wide and easily adjustable bandgap energy, so the device can be used variously as light emitting devices, light receiving devices and various kinds of diodes.
In particular, light emitting devices such as light emitting diodes and laser diodes obtained by using group III-V or group II-VI compound semiconductor substances can implement light having various wavelength band such as red, green, blue and ultraviolet rays due to the development of thin film growth technology and device materials. In addition, the light emitting devices such as light emitting diodes and laser diodes obtained by using group III-V or group II-VI compound semiconductor substances can implement a white light source having high efficiency by using fluorescent substances or combining colors. Such a light emitting device has advantages such as low power consumption, semi-permanent lifetime, quick response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps.
In addition, when a light receiving device such as a photodetector or a solar cell is manufactured using the group III-V or group II-VI compound semiconductor substances, a photoelectric current is generated by absorbing light having various wavelength domains with the development of device materials, so that light having various wavelength domains such as from gamma rays to radio waves can be used. In addition, the above light receiving device has advantages such as quick response speed, safety, environmental friendliness and easy control of device materials, so that the light receiving device can be easily used for a power control, a super-high frequency circuit or a communication module.
Accordingly, the semiconductor device has been applied and expanded to a transmission module of an optical communication tool, a light emitting diode backlight replacing a cold cathode fluorescence lamp (CCFL) constituting a backlight of a liquid crystal display (LCD), a white light emitting diode lighting apparatus replaceable with a fluorescent lamp or an incandescent bulb, a vehicular headlight, a traffic light and a sensor for detecting gas or fire. In addition, the applications of the semiconductor device can be expanded to a high frequency application circuit, a power control apparatus, or a communication module.
For example, the light emitting device may be provided as a p-n junction diode having a characteristic in which electrical energy is converted into light energy by using a group III-V element or a group II-VI element in the periodic table, and various wavelengths can be realized by adjusting the composition ratio of the compound semiconductor substances.
For example, since a nitride semiconductor has high thermal stability and wide bandgap energy, it has received great attention in the field of development of optical devices and high power electronic devices. Particularly, a blue light emitting device, a green light emitting device, an ultraviolet (UV) light emitting device, and a red light emitting device using the nitride semiconductor are commercialized and widely used.
For example, the ultraviolet light emitting device refers to a light emitting diode that generates light distributed in a wavelength range of 200 nm to 400 nm. In the above wavelength range, a short wavelength may be used for sterilization, purification or the like and a long wavelength may be used for a stepper, a curing apparatus or the like.
Ultraviolet rays may be classified into UV-A (315 nm to 400 nm), UV-B (280 nm to 315 nm) and UV-C (200 nm to 280 nm) in an order of the long wavelength. The UV-A (315 nm to 400 nm) domain is applied to various fields such as industrial UV curing, curing of printing ink, exposure machine, discrimination of counterfeit money, photocatalytic sterilization, special lighting (such as aquarium/agriculture), the UV-B (280 nm to 315 nm) domain is applied to medical use, and the UV-C (200 nm to 280 nm) domain is applied to air purification, water purification, sterilization products and the like.
In addition, as a semiconductor device capable of providing a high output has been requested, studies on a semiconductor device capable of increasing an output power by applying a high-power source have been proceeding.
In addition, as for a semiconductor device package, studies on a method of improving the light extraction efficiency of a semiconductor device and improving the light intensity in a package stage have been proceeding. In addition, as for the semiconductor device package, studies on a method of improving bonding strength between a package electrode and a semiconductor device have been proceeding.
In addition, as for the semiconductor device package, studies on a method of reducing the manufacturing cost and improving the manufacturing yield by improving the process efficiency and changing the structure have been proceeding.